The present invention generally relates to the field of stabilized equipment supports, and more particularly, to an apparatus for supporting hand-held cameras or other equipment which may be orientation-sensitive and/or stability-sensitive so that such equipment is isolated from unwanted motions while in operation.
Many different types of "hand-held" cameras have been developed, virtually since the beginning of photography. Whether for still pictures or for motion pictures, as a result of the artistic needs of such media, virtually every such model of camera which was light enough to be lifted has at some times been "held" by a human operator. However, in each case, the inherent instability of such equipment immediately became a corresponding factor. Such difficulties are further multiplied when motion pictures are involved, since the operator may now need to walk and at time even run with the camera to obtain the necessary motion picture images.
Responsive to this, devices of the type described in U.S. Pat. No. 32,213 (Brown), and later U.S. Patent No. 4,208,028 (Brown et al), were developed. Such devices generally approached the problem of camera stabilization by providing a spring-loaded equipoising arm for supporting a gimbal-mounted expanded camera system. The disclosed unit serves to isolate the camera from both angular and spacial motions and has proved to be quite effective in allowing the camera operator to produce exceedingly stable images in a variety of different situations. As a consequence, such devices have since become standard tools in the motion picture and video industries, operating to satisfy a variety of the needs in such industries.
Such devices were primarily designed to support relatively large film and video cameras, exhibiting significant weights. Even the lightest of cameras contemplated for use in connection with such systems were on the order of twenty pounds, and it is presently not uncommon for complete systems (including the stabilized mounting, camera, and supporting equipment) to exceed ninety pounds as operating requirements become more varied and complex. However, such devices were considered to be unsuitable for adaptation to cameras which were significantly lighter than those conventionally employed in the motion picture and video industries.
Subsequently, camera technology evolved to the point where portable video cameras became available which were primarily directed toward consumer-oriented applications. A variety of formats for this product were initially developed, with continued efforts toward miniaturization and simplification due to the unit's consumer-oriented market. Initial attempts at developing an independent, fully self-sufficient consumer video camera (i.e., "CamCorder") involved the so-called "full-sized" CamCorders, self-contained camera and recording units designed to rest on the shoulder of the operator, with a viewfinder mounted forward and to the side of the resulting unit. Following this, the so-called "compact" CamCorders were developed, which rapidly captured a significant portion of the consumer market. These "compact" CamCorders were sufficiently small to be supported entirely by the hand (or hands) of the operator (rather than being placed over the operator's shoulder), with the camera held in front of the operator's face, and with the viewfinder (generally top-mounted) in close proximity to the operator's eye.
By virtue of their appeal to the general consumer, a large number of "compact" CamCorders were sold. However, such units, as a result of the manner in which they are supported by the camera's operator, were found to be inherently unstable. In addition to their inherent instability, such "compact" CamCorders were being operated by amateur photographers, still further complicating matters. The common result was an unstable and often unacceptable video image. This was particularly so when the operator departed from a stationary position, and attempted ambulatory operations of the unit.
U.S. Pat. No. 4,946,272 (Brown) discloses a stabilized equipment support which is particularly suited to accommodate, and substantially eliminate the inherent instability of a "compact" CamCorder, to permit highly stable, professional video images to be obtained making use of conventionally available "compact" CamCorders. This was achieved by providing a stabilized support which is both small and light-weight in construction, and which is capable of receiving the equipment with which it is to be used upon an expanded support network which complements the supported equipment in a manner which alters the position of its center of gravity so that the resulting unit can be effectively supported at its center of gravity using a novel handle assembly.
As disclosed, the equipment support is generally comprised of a platform for receiving the equipment (a camera), which is counter-balanced by a viewfinding device and a battery or batteries for operating the equipment. Appropriately configured struts are preferably used to interconnect the platform and the viewfinding device, and to provide support for the system's battery or batteries. The platform further preferably incorporates an adjustment mechanism (e.g., an "x-y" table) for permitting relative adjustment between the equipment receiving platform and the handle which supports the assembly, to achieve an appropriate balance of the resulting unit. This adjustment mechanism includes a fitting for receiving the handle which supports the platform, at a position which intersects with the center of gravity of the equipment and the supporting system which receives it, to achieve an appropriate static balance of the resulting unit about each of three mutually perpendicular axes.
The disclosed supporting handle preferably takes the form of a two-part (i.e., "interrupted") handle which is generally comprised of a major portion which can be engaged for overall support and transport of the unit, and a minor portion which includes a generally cylindrical control surface which is accessible by the hand (preferably the thumb and index finger) to achieve controlled orientation of the equipment support, which are separated by an appropriate device for providing mutual isolation between the two portions of the compound handle. Preferably, the isolation device which separates the two distinct portions of the handle is a gimbal or other device which provides angular isolation about three generally perpendicular axes, while being virtually frictionless as well as freely pivotable and rotatable to permit proper control of the equipment and its support. As a result, the handle not only operates to receive forces for both support and transport of the equipment, but also to appropriately orient the device while functioning to provide mutual isolation between the supported equipment and the angular influence of the forces which are applied to the handle.
Further evolution in camera technology has since resulted in still further miniaturization and simplification of the hand-held CamCorder. Indeed, hand-held CamCorders have since been developed which are sufficiently small to fit within the palm of the operator's hand, which have come to be known as "PalmCorders". Such PalmCorders are fully adaptable for use in conjunction with the stabilized equipment support which is disclosed in U.S. Pat. No. 4,946,272, achieving commensurate improvements in operational stability and in the quality of the video images which can be produced. However, in practice, two factors were found to exist in conjunction with operations of such equipment which were peculiar to PalmCorders, and which needed to be addressed.
First, the popularity of PalmCorders primarily stems from their compactness, and their ability to be handled much like consumer-grade still cameras. Such compactness and ease of use was at times compromised when combined with a stabilized equipment support such as is disclosed in U.S. Pat. No. 4,946,272, since the need then arose to carry a separate device which was somewhat larger than the PalmCorder itself. This not only required the operator to carry two different pieces of equipment for obtaining stabilized video images, but also required either an assembly of the respective units when their use was desired, or a preassembly of such units for "ready-to-use" applications. In each case, this necessitated the accommodation of equipment significantly larger than the PalmCorder in and of itself.
Second, the weight of a PalmCorder is significantly reduced, even from the relatively light "compact" CamCorders. It was found that this significant reduction in weight could at times increase the tendency of the assembled equipment support to "precess" in a manner which tended to compromise its overall operations. The phenomenon of "precession" is best considered when comparing the static balance of the stabilized equipment support with its dynamic balance, particularly during rapid panning of the camera. In static balance, the center of gravity for the unit is placed in alignment with the central axis which is generally defined by the handle of the stabilized equipment support. Such static balance can be established, and maintained when the expanded components of the stabilized equipment support are placed in any of a variety of different locations relative to the handle (and the center of gravity). However, this desired relationship is not necessarily maintained in dynamic operation.
Ideally, movement of the camera, and the stabilized equipment support, should cause rotations along an axis which is parallel to the central axis defined by the handle of the stabilized equipment support. However, in practice, this relationship is not necessarily maintained (depending upon the expanded arrangement of components associated with the stabilized equipment support). In such cases, rotations (e.g., resulting from panning of the camera and the stabilized equipment support) will tend to occur about an axis which is disposed at an angle relative to the central axis defined by the handle. This, in turn, causes the camera to precess about the handle when in this configuration, which is exhibited as an unintentional wobble of the resulting unit toward the true (central) axis of the system.
It therefore became desirable to adapt the stabilized equipment support which is disclosed in U.S. Pat. No. 4,946,272 so that the fundamental improvements of this device could be achieved in conjunction with PalmCorders and other miniaturized camera equipment of this general type.